Method of preserving wood.



PA' IENTED MAR. 20, 1906.

J. B. CARD.

METHOD OF PRBSERVING WOOD.

'APPLIOATIOH FILED FEB. 3,1905.

JOSEPH B. CARD, OF CHICAGO, ILLINOIS.

METHOD OF PRESERVING wooD.

Specification of Letters Patent,

I Patented March 20, 1906.

Application filed February 6, 1905. "SerialNo. 244,467-

.io a'ZZ whom it may concern:

' Be it known that I, JOSEPH B. CARD, a citi zen of the United States, residing at Chicago, I

in the county of Cook and State of Illinois, have invented a new and Improved Method of Preserving Wood, of which the following is a. specification, reference being had to the accompanying drawings.

My invention relates to a new and improved method of preserving wood, especially railroad-ties, and especially to a new and improved process of preserving Wood in i which a mixture of preservative fluids of different specific gravities is employed.

As is well known, in order to prevent, the

decay of railroad-ties and other wooden articles which are .exposed to the Weather it has been customary to treat them to a preservative process consisting of the application to and absorption by the wood of preservative and antiseptic liquids. One method very commonly used for such treatment-consists in lacing the ties in a tank or suitablerece tac e adapted to be closed water andfair tig t and after the ties have been placed in the receptacle'filling the receptacle, so as 'to completel submerge the ties with the preservative uid and allowingthem to'remain submerged in the fluid fora suitable length of time tocause the preservative fluid to thoroughly enter the pores and saturate the wood. It has also been customary to apply pressure to the tank full of preservative liquid, so that it-may be contained in the tank under considerable ressure to assist the preservative process. arious forms of apparatus have also been designed to carry out this process. It has alsobeen customary as preliminary to the application of the preservative flui to first steam the ties in the preserving-chamber and after steaming to subject them to more or less of a vacuum in order to assist the thorough impre ation of the woodwith the preservative ffli id or fluids. Other methods -have also been devised, such as forcibl spraying the ties in a containing-tank with the preservative. fluid. A preservative fluid commonly used in suchprocess is a suitable.

solution of chlorid of zinc. A difficulty arising from the use of chlorid of .zinc or a'similar preservative or antise tic fluid arises from the act that when such uid is used alone itwill g leach out of the tie or be washed out gradually by the action of the weather.

To overcome this, creosote or somellquid-tar prepag ratigri has beenused in connection with the 'chlorid-of-zinc solution for the purpose of stopping the pores of the wood and preventmixture of a solution of chlorid of zinc and some similar preservative or creosote or some similar substance is used, a great difficulty arises from the different specific gravities of the two liquids and from their not mixing properly. The ordinary creosote-oil purchasable on the market in this countryis usuall of much less specific gravity than the c orid-of-zinc solution which is ordinarily used, containing such proportion of chlorid of zinc as is best forthe preservative rocesses. It therefore follows that no matter liow thor: ou hly the preservative fluids Ina be mixed be ore entering the tank under t e ap lication of pressure and during the length 0 time that it is necessary that the ties should be submerged in order to securetheir thorough impregnation the heavier liquid-that is to say, the zinc solutionsettles'to the bottom and the li hterthat is to say, the creosote rises to t e top. It is obvious that this causes the ties at. the top of the tank to receive too great a proportion of creosote and too small a proportion of the chlorid-of-zinc solution for the purposes for which'said liquids are used, while with the ties at the bot tomof the tank the reverse is the case. It results that the ties are notcvenlyimpregnated and even that some may receive a wholly insufficient quantity of creosote to r0 erl effect the reserving. rocess. This iffifzullfy has been recognized and various means suggested for'overcoming it, none of which, however, are thoroughly successful in practice, and manufacturers have been obliged to import from Germany and at reat expense specially-prepared creosote o the same specific grayity as the chlorid-ofzinc solution.

My improved process is especially directed to overcoming the difficulties above set forth, and I overcome the difficulties above suggested by agitating the mixed liquids while they are contained inthe tank and maintained at a constant pressure so thoroughly as to prevent the separation of the liquids or Wooden articles to be treated in an inclosed vessel'capable of being tightly sealed, in filling the vessel thus closed with a mixture of preservative fluids, preferably chlorid-of-zinc solution and creosote, so as to completely submerge the ties, placing and maintaining a constant pressure upon the liquids for a suitable length of time to impregnate the ties, and in agitating the liquids in the closed tank While the constant pressure is maintained in the tank during the time of the subjection of the wood to the treatment.

I have also deviseda new and improved apparatus for the carrying out of the above process and illustrated in the accompanying drawing.

In the drawing the figure is an isometric view of my new and improved apparatus, broken away in certain places to show the interior structures.

Referring to the drawing, 2 indicates a tank adapted to contain preservative fluid.

3 indicates a cylinder or chamber which is closed at one end and provided with a door 4 at the other end which is adapted to be closed upon the cylinder, so as to make it air and water tight under pressure and which is secured in place to the end of the cylinder 3 in an well-known and approved manner. The cy inder 3, as shown, 1s preferably ofa size adapted to take in several car-loads of ties and is provided at its bottom with tracks 5, upon which cars loaded with ties 7 are run in the cylinder, so as to nearl fill the same from end to end and to near t ..e top.

8 indicates a pipe which leads out of the tank 2 and opens up into the cylinder 3, preferably at the bottom thereof, as shown. The pipe 8 is provided at a suitable place with a gate-valve 9.

10 indicates a by-pass pipe which opens up into the main pipe 8 upon each side of the valve 9 and is provided with-a ressure-valve 11, which ma be of an we l-known form and construction and which is adapted when the pressure in the cylinder 3, .produced as heremafter described, exceeds a predetermined amount to open and relieve the pressure.

12 indicates a by-pass pipe which opens out of the pipe 8, between t .e valve 9 and the tank 2, into a pump 13. The pump 13 may be of any well-known form and mode of operation. V

15 indicates a pipe which leads from the pump 13 and opens into the pipe 8 beyond the valve 9.

16 indicates a pipe which leads from any suitable source of steam-supply (not shown) and leads into the cylinder 3, where it opens into a perforated pipe 17, which extends along the bottom of the cylinder 3.

18 indicates a valve suitably placed in the pipe 16.

19 indicates a fan which may be driven in either direction, and hence used, as hereinafter described, either to produce a partial vacuum in the cylinder 3 or to force air into the cylinder 3. The fan 19 may be of any suitable construction and mode of o eration and ispower-driven from any suitab e source of supply. (Not shown.)

20 indicates a pipe which leads from the fan 19 into the top of the cylinder 3 and is provided with a valve 21, adapted to open and close the pipe 20.

. 22 indicates an exhaust-pi e which leads from a suitable elbow 23 in t e pipe 20 and opens intothe atmosphere.

24 indicates a valve in the pipe 22 above its junction with the pipe 20.

25 indicates a rotary pump, which may be of any well-known and approved form and construction.

26 indicates a pipe which leads from the pump 25 and opens into-the top of the cylin- 27 indicates a ipe which leads from the discharge side of the pump 25 and opens into a pipe 28, which leads, by means of a number of branches 29, into thec linder 3. I prefer to dispose of these'branc pipes in substan tially the manner shown in the drawing; but their position and points of o ening into the tank may of course be varie as may be desired.

The com lete operation of my process and of the ,meciianism above described is as follows: The tank 2 is sup lied with a suitable mixture of preservative uids. I referto use a mixture of a four-per-cent. c orid-of-zinc solution and creosote in the proportions of eighty-eight per cent of the four-per-cent. chlorid-Of-zinc solution and twelve er cent. of. creosote. These. proportions, owever, may be varied as the nature of the work to be performed may dictate. The valve 9- is closed. The door 4 being removed, the cylinder 3 is loaded with the ties or other similar articles to which the preservative process is to be applied. As was said above,- the most economical and referable way is to load the ties'upon suitab e cars and run them into the cylinder, the cylinder being of suitable size, as was said above,'for such, purpose. The door 4 is then laced in position and securely locked in p ace so as to render the cylinder 3 air-tight and water-tight under pressure. The valves 18 and 24'are then opened, the valve 21 closed, and steam is allowed to flow through the pi e 16 and the perforated pipe 17 into the cy inder 3, the air being driven out through the pipe 22. When the cylinder 3 is filled with steam, the valve 24 is closed pump is then set in motlon.

I and steam continued to be supplied throu h I When the ties have been steamed a suitable length of time, the valve 18 is closed, the

valve 21 opened, and the fan 19 driven so as to operate as an exhaust-fan, whereby-the steam will be drawn from the cylinder 3 and a. partial vacuum produced in the cylinder. The portion of the process so far described will extract the sa and other obstruction from the pores of t e ties and open them to the action of the preservative fluid. The

valve 21 is then closed, the valve 9 opened, and the cylinder 3 is filled 'from the tank 2 with. the preservative mixture. When the clyl linder 3 is filled, the valve 9 is closed and t e pump 13 set in operation until a suitable pressure, preferably approximately one hundred pounds to the square'inch, is set up in the cylinder 3 and in the liquid therein contained, the pressure being maintained thereafter by a slower but suitable operation of the pump 13. In case at any time the pressure exceeds the desired amount the pressurevalve 11, which is regulated accordinfgly, ow

opens, anda passage being opened to the o the liquid 11), the pipe 8 u on both sides of the valve 9 the pressure Wll dro until the pressure-valve 11 closes again.- he rotary By the operation of thejpump the liquid is drawn from the cylinder 3 through the pipe'26 and forced through the pipes 27 and 28 and branch pipes. 29 back again into the tank 2; It isobvious that as. the ap aratus shown is constructed there is a close circuit for the liquid through the pipe 26, pump 25, and pipes 27, 28 and 29 back into the tank again and that t erefore the constant pressure maintained in the tank by'the pump 13, as above described, is maintained. By the withdrawal of the liquid from the tank and its dischar e into the tank again through theo erationo the pum 25 still under ressure t e preservative-flui mixture contamed in the cylinder 3. will be agitated sufiiciently to. keep the liquids thor- I oughly mixed and to prevent the settling of the heavier during the entire length of tlme to which the ties are sub'ected to the treatment. The time re uire for their thorough impregnation will 0 course vary, both with the kind of wood in the ties and to a certain extent with the .character and nature of the preservative fluids used. With the mixtures described and which I prefer to use, the average length of time for which the ties should be subjected to the process in order to'lthor-v oughly-impregnate them will be approximately three hours. When the, ties are sufficiently impregnated, the pumps 13 and 25 v .desire to secure by of chlorid-of-zmc solut on and creosote above 60.

are sto ped, the valve 9 opened, the valve 21 opene and the fanset going in the opposite dlrectionto force air into the cylinder 3. The valves 24 and 18 bein of course closed, the forcing of the air into the cylinder 3 will drive 2 ready to be used agaln. When the cylinder is emptied, the fan 19 is stopped, thevalve 20 opened, the valve 9 closed, the door 4 removed, and the ties thus impregnated removed from the cylinder.

I have shown and described the above apparatus as .a new and improved apparatus adapted to the practicing of my new and improved method, and that is the form of apparatus which I prefer to use. It isobvious, however, that other forms of apparatus might be used for the racticin of my newmethod. I have also s own an described a rotary pump 25 as the mechanism in my new and improved a paratus-by which the .ag1tation of the li ui s under pressure in the tank is brought a out during the process of the treatment. This is the means which I prefer to use, the pump of coursebein constructed of a suflicient capacity to circu ate and agitate the preserving fluids in the .cylihdersufficiently to keep them constantly mixed duringthe treatment'of the ties and to prevent the one of greater specificgravity settling at the bottom of the cylinder, the pressure upon the liquid out of the cylinder 3 into the tank the liquids being, as has been described, constantly maintained by the pump 13. It is obvious, however, that other means might be devised for producing this agitation of the preservative mixture. I have also shown the a 'tating apparatus so constructed and place as to draw'the liquid from the to of the tank and force it'into the bottom. his, is theform inwhich I prefer to construct it; but it is obvious that the li uid might be drawn from and forced into t e tank from other points, and I do not limit my invention with reference to pipes so placed. It is obvious also that a suitable pressure might be brought into the tank and maintained therein by other means than by the Igum 13. This, however, is the mechanism w 'ch prefer to use.

I have described my new pr cess as pecul iarly adapted to the treatme t of wooden .articles-such as railway-ties, for instance. It is obvious, however, t at my process may be used for the reservative treatment of other things, and do not limit myself in 1t s use to t e treatment of wood.

' That whichI claim as m invention, and

of preserving wood and I is impregnated, and in circulating the said mixture in the tank while said mixture is maintained under pressure .and during said im regnatingprocess to cause the thorough an .constant mixture of-said fluids during said treatment. i

2. The method of preserving wood and similar material by the use of a mixture of preservative fluids of difierent specific gravity, which consists in submerging the wood in a mixture of said fluids in a closed receptaole, subjecting said preservative fluids to and maintaining them under pressure until the wood is impregnated, and in circulating the said mixture in the tank while said mixture is maintained under pressure and during said im regnating process to cause the thorough an constant mixture of said fluids during said treatment.

- 3. The preservative method, which consists insubmer ing the material to be treated in a mlxture o chlorld-of-zlnc solutlon and.

creosote in a closed receptacle, subjecting said mixture to and maintaining it under pressure in said receptacle until the material to be treated is impre nated, and a itating the said mixture in sai rece tacle wliile under pressure to keep the said uids thoroughly mixed and prevent the settling of the heavier durin the treatment.

4. %he method of preserving Wood and similar material by use of a mixture of preservative fluids of different specific gravity, which consists in lacing the wood in a rece tacle, closin said receptacle and filling t e same with t e fluid mixture, applying and maintaining pressure to said fluid mixture in said closed receptacle and simultaneously circulating the fluid contents while said fluid contents are maintained under fluid-pressure and during the impregnating rocess, and then forcing the preservative iiuid by airpressure back out of said closed receptacle and back into a reservoir, substantially as described.

JOSEPH B. CARD.

Witnesses:

C. E. PICKARD, MINNrE- A. HUNTER. 

